Buggy code:
public void _instanceof ( int pc , int index , IConstantPoolEntry constantClass ) { } public void _invokeinterface ( int pc , int index , byte nargs , IConstantPoolEntry constantInterfaceMethodref ) { } public void _invokespecial ( int pc , int index , IConstantPoolEntry constantMethodref ) { } public void _invokestatic ( int pc , int index , IConstantPoolEntry constantMethodref ) { } public void _invokevirtual ( int pc , int index , IConstantPoolEntry constantMethodref ) { } public void _ior ( int pc ) { } public void _irem ( int pc ) { } public void _ireturn ( int pc ) { } public void _ishl ( int pc ) { } public void _ishr ( int pc ) { } public void _istore_0 ( int pc ) { } public void _istore_1 ( int pc ) { } public void _istore_2 ( int pc ) { } public void _istore_3 ( int pc ) { } public void _istore ( int pc , int index ) { } public void _isub ( int pc ) { } public void _iushr ( int pc ) { } public void _ixor ( int pc ) { } public void _jsr_w ( int pc , int branchOffset ) { } public void _jsr ( int pc , int branchOffset ) { } public void _l2d ( int pc ) { } public void _l2f ( int pc ) { } public void _l2i ( int pc ) { } public void _ladd ( int pc ) { } public void _laload ( int pc ) { } public void _land ( int pc ) { } public void _lastore ( int pc ) { } public void _lcmp ( int pc ) { } public void _lconst_0 ( int pc ) { } public void _lconst_1 ( int pc ) { } public void _ldc_w ( int pc , int index , IConstantPoolEntry constantPoolEntry ) { } public void _ldc ( int pc , int index , IConstantPoolEntry constantPoolEntry ) { } public void _ldc2_w ( int pc , int index , IConstantPoolEntry constantPoolEntry ) { } public void _ldiv ( int pc ) { } public void _lload_0 ( int pc ) { } public void _lload_1 ( int pc ) { } public void _lload_2 ( int pc ) { } public void _lload_3 ( int pc ) { } public void _lload ( int pc , int index ) { } public void _lmul ( int pc ) { } public void _lneg ( int pc ) { } public void _lookupswitch ( int pc , int defaultoffset , int npairs , int [ ] [ ] offset_pairs ) { } public void _lor ( int pc ) { } public void _lrem ( int pc ) { } public void _lreturn ( int pc ) { } public void _lshl ( int pc ) { } public void _lshr ( int pc ) { } public void _lstore_0 ( int pc ) { } public void _lstore_1 ( int pc ) { } public void _lstore_2 ( int pc ) { } public void _lstore_3 ( int pc ) { } public void _lstore ( int pc , int index ) { } public void _lsub ( int pc ) { } public void _lushr ( int pc ) { } public void _lxor ( int pc ) { } public void _monitorenter ( int pc ) { } public void _monitorexit ( int pc ) { } public void _multianewarray ( int pc , int index , int dimensions , IConstantPoolEntry constantClass ) { } public void _new ( int pc , int index , IConstantPoolEntry constantClass ) { } public void _newarray ( int pc , int atype ) { } public void _nop ( int pc ) { } public void _pop ( int pc ) { } public void _pop2 ( int pc ) { } public void _putfield ( int pc , int index , IConstantPoolEntry constantFieldref ) { } public void _putstatic ( int pc , int index , IConstantPoolEntry constantFieldref ) { } private char [ ] returnFieldrefDescriptor ( IConstantPoolEntry constantFieldref ) throws IllegalArgumentException { } public void _ret ( int pc , int index ) { } public void _return ( int pc ) { } public void _saload ( int pc ) { } public void _sastore ( int pc ) { } public void _sipush ( int pc , short value ) { } public void _swap ( int pc ) { } public void _tableswitch ( int pc , int defaultoffset , int low , int high , int [ ] jump_offsets ) { } public void _wide ( int pc , int iincopcode , int index , int _const ) { } public void _wide ( int pc , int opcode , int index ) { } public void _breakpoint ( int pc ) { } public void _impdep1 ( int pc ) { } public void _impdep2 ( int pc ) { } private void appendDimensions ( int dimensions ) { } private void appendGetArrayType ( int atype ) { } private String returnConstantClassName ( IConstantPoolEntry constantClass ) { } private String returnDeclaringClassName ( IConstantPoolEntry constantRef ) { } private char [ ] [ ] getParameterNames ( char [ ] methodDescriptor ) { } private void appendOutputForConstantDouble ( IConstantPoolEntry constantPoolEntry ) { } private void appendOutputForConstantLong ( IConstantPoolEntry constantPoolEntry ) { } private void appendOutputForConstantString ( IConstantPoolEntry constantPoolEntry ) { <START_BUG> this . buffer . append ( "<String<seq2seq4repair_space>" ) . append ( constantPoolEntry . getStringValue ( ) ) . append ( "\">" ) ; <END_BUG> } private void appendOutputforConstantInteger ( IConstantPoolEntry constantPoolEntry ) { } private void appendOutputforConstantFloat ( IConstantPoolEntry constantPoolEntry ) { } private void writeNewLine ( ) { } private void writeTabs ( ) { } private void writeExtraTabs ( int extraTabs ) { } }

Fix:
this . buffer . append ( "<String<seq2seq4repair_space>\"" ) . append ( constantPoolEntry . getStringValue ( ) ) . append ( "\">" ) ;